2008 BMW 135i: Speed Limiter
July 28, 2009
Give it up for brand-specific internet fansites. Get past all the flame wars and troll fests and you'll always find a few sharp guys and gals.
After I posted up our 2008 BMW 135i's dyno comparison geek-out a few weeks back, one or two members of e90post.com pointed out that I incorrectly stated that our car's stock redline was 6500 rpm.
Although the engine's speed ceased to increase beyond 6500 rpm while on the dyno, those chaps are correct. Here's why.
The key bit is that our longterm 135i does not have the Sport Package. See, BMW governs non-Sport Package-equipped 135is to 135 mph. Sport Package versions enjoy a 155-mph speed limiter.
On the dyno, I was caning the 135i in fourth gear, which can reach 135 mph before the rev limiter is touched. The car simply shuts down the party when 135 mph is reached. In fourth gear, 135 mph happens to be right around 6500 rpm.
Had I dynoed in third gear instead, our 135i would have gone all the way to 7000 rpm.
A little digging around suggests that the Sport Package included summer tires with a higher speed rating than the rubber on the non-Sport Package versions. It's fairly impressive that BMW didn't simply emasculate all versions of the 135i just to account for the lowest-common denominator trim level.
And while this distinction doesn't have too much relevance in the US, I'm sure autobahn users appreciate it.
Jason Kavanagh, Engineering Editor